A 60 minute lesson in which students will add and subtract fractions with related denominators.
This lesson contains a link to an external video. Please watch the video prior to presenting this lesson to ensure that the content is appropriate for your students.
Draw a large circle on the board and divide it into sixths. Ask a student to come up to the board and colour in one piece. Underneath the circle, write one sixth as a fraction.
Draw an addition sign next to the first circle, then draw a second circle of the same size. Divide this second circle into thirds. Ask a second student to come up to board and colour in two pieces. Underneath the circle, write two thirds as a fraction.
Draw an equals sign next to the second circle, then draw a third circle of the same size. Before dividing this third circle, ask the students:
How is this example different from the example we looked at last lesson?
Does this example present a problem? What is it?
Is it possible to add these two fractions? If so, how?
Discuss the steps involved in adding and subtracting related fractions, as outlined on slide 12 of the Adding and Subtracting Fractions PowerPoint. Encourage the students to suggest some examples of related fractions.
Display and discuss the first annotated example on slide 13 (this is the same as the example drawn on the board). On the board, draw three more circles to represent the same addition question, divided into sixths. Ask a students to come up to the board and colour in the correct number of pieces in each circle. Emphasise that the addition is now possible because the fractions share a common denominator.
Display and discuss the second and third annotated examples on slides 14-15. Emphasise the importance of reducing the answer to its lowest terms and converting any improper fractions to mixed numerals.
Display the review questions on slide 16. Monitor and support the students as they individually complete the questions on the slide.
Display and discuss the answers to the review questions on slide 17. As the students correct their answers, encourage them to raise any queries or concerns.